Power hoist for dump trucks



1 2 June 9 7 R. F. CRAWFORD POWER HOIST FOR DUMP TRUCKS Filed May 5.1926 6 Sheets-Sheet. Jnwntoc 1Q /cawfnd ftm 1927. June Y R. F. CRAWFORDPOWER HQIST FOR DUMP TRUCKS w s Sheets-Sheet 2 d May 5, l

1 27. June 9 R. F. CRAWFORD POWER HOIST FOR DUMP TRUCKS Filed May 5.1926 6 sheets-sheet, 5

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June 28. I927.

W W M M 3 GJ Q m bl q -l Q w I n l llllk U "w I m u w u l luufi mPatented as 2a, 1927.

PATENT OFFICE.

RALPH F. CRAWFORD, 0F SALINA, KANSAS.

POWER HOIST FOR DUMP TRUCKS.

Application filed May 5,

The invention has relation to power hoists for dump trucks, having foran object the.

provision of an improved means for the pur pose wherein a plurality ofhoisting speeds and a reverse for lowering the body may be obtained withamaximum of simplicity, and

wherein the truck body may be mounted at a lesser height and at a pointfartherforward on the chassis than is now possible with devices of thischaracter. According to this invention power is derived directly fromthe motor of the truck, being taken off from the propeller shaft in rearof the transmission. Automatic control devices are also provided wherebythe mechanism may operate automatically with the greatest possibleefliciency.

The invention consists in the novel construction and combination ofparts as set forth in the appended claim.

In the accompanying drawings, illustrating the invention, Fig. 1 is aside view of a dump truck embodying the invention. Fig. 2 is a plan viewof the same. Fig. 3 is a detailed cross-sectional view 'of the clutchand hoist take-off devices. Fig. 4 is a detailed plan view of the hoistgearing and arms. Fig. 5 is a side view of the same. Fig. 6 is a sideviewof a truck equipped with a modified form of hoist mechanism.

Fig. 7 is a plan view of the same. In thesedrawings numeral 1 designatesthe propeller shaft of the truck, said shaft being divided immediatelyin rear of the well-known transmission mechanism and equipped with aclutch 2 having a member 3, adjustable by a suitable means, controlledfrom the cab of the truck, into any one of three positions, a centralneutral position, a rearward position for effecting a clutch between theforward and rear halves of the propeller shaft, and a forward position.efiecting a clutch be tween the forward half of the propeller shaft andthe hoist take-off. In the forward position, the clutch member engagessuitable clutch teeth 4 in bevel gear member 5, meshing with a bevelgear 6 on countershaft 7, upon which is mounted a worm gear 8. Worm gear8 meshes with a pinion 9, fastupon shaft 10, suitably supported from thechassis and provided with universal joints 11 and at its rear end with aworm gear 12. The counter-shaft is mounted in bearings of the frame, andprovided with opposite lift ing arms 14, 14 and also with a segment gearmeshing with wormgear 12. The

1926. Serial no. 106,944.

pair of transverse spacing beams 20, 20 upon 7 which the body normallyrests.

The arrangement of the hoisting mechanism, is such that the beams 20 maysupport the body within about 4 inches of the main frame, so that thebody is mounted much lower than is common in trucks of this char acter.It will also be observed that the h0ist ing mechanism is locatedentirely below the dump body, so that this body may be mounted wellforward, with a minimum clearance between the same and the cab.

The gears 12 and 15. are enclosed in a housing 21, so that they may berun in oil.

lVith the arrangement. described, member being in clutch with the teeth4, the hoisting gears are in connection with the drive shaft motor, andmay be operated at any of the speeds provided by the transmission. Theworm gears 8 and 12 will act as brakes in maintaining the body inhoisted position after the clutch 2 has been disengaged, and lowering ofthe body may be accomplished by throwing the transmission mechanism intoreverse, and engaging member 3 with the teeth 4.

In the modified form of the invention shown in Figs. 6 and 7 the sameclutch devices are employed, whereby a shaft 22 may be driven to hoistthe body. Shaft 22 extends transversely of the main frame and isprovided at its opposite ends with drums 23, 23 whereon suitable cablesor chains 24, 24 are wound, said chains extending rearwardly and beingattached to members of opposite sets of toggle links 25, 26. The members25 of the toggle links are pivoted in bearings of the main frame, thelinks 26 being pivoted to the dump body. When shaft 22 is clutched tothe drive the cables 24 are wound upon drums 23 and the toggle links25,26 are straightened into the dotted line position shown in Fig. 6. Inorder to give the cables 24 better leverage in starting the hoist, arms27, 28 are extended from the links 25, 26 and provided at their freeends with pulleys engaging the cables, these arms extending toward each.other and lying one angles against'the arms 27,128 until the togglelinks have been opened to a position providi j suflieient leverage forthe hoist in this form of the invention a brake 29 is provided uponshaft 22,.whereby'the'body may be held in hoisted position.

in order to provide for theautoinatie disengagement of clutch 2 when thebody has been brought to the fully raised position, a plun er 30 ismounted on the housing 21 in pos ion to be operated by segment 15 as thelatter is fed by the Worm 12 to its extreme position. Plunger 30contacts with an interniediate y pivoted. lever '31 connected 'to a rod52, extended forwardly beneath the cab and provided with an operatingconnection for the clutch control lever 34. Rod 32 inay also *ha veeanoperating connection 35 with the throttle lever 36, whereby the throttleshay be operated and the fuel supply to the motor automaticallydecreased.

1 claim: 7 V

In a hoist for dump truck bodies the coinb'inati'oii i'v'i't h 'inotor,fuel supply means therefor having a throttle, a pivoted dump body,hoisting mechanism therefor, and a power connection between said motorand said hoisting inechanis'in including a clutch,

of means operable by said hoisting mechanisni toop'ei'a t'ethe'th'rottl'e in said fuel sup- 30 ply ineans end to disengage saidClutch.

In testimony whereof I afiix my signature.

RALPH F. 'onitwroen

